Estimate of Heating of Modular Coil From Un-Insulated VV during Bakeout

1. Estimate of Heating of Modular Coil From Un-Insulated VV during Bakeout • Estimate of Heat Load • Estimate of LN2 heating based on heat balance • Estimate of Coil and Clamp Heating

2. Estimate of Un-insulated Coil Heating by 350 C VV

3. Assumptions • Radiative Heating Only • Based on Emissivity of VV and Clamps/Coils = 0.3 • Effective Heat Flux 1500 w/m2 • LN2 Coiling in Tubes • Convection off base of MCWF Max Temperatures Clamp 206 K Coil 108 K

4. Temperature Sensitivity to Emissivity

5. Can we detect an un-Insulated VV during Bakeout to 150C? • Simple 1 unit cell model of VV Shell • Heated by Bakeout tubes mounted to one corner • Radiatively cooled to Modular Coils at 80K • Emissivity assumed 0.4 • Higher Values would be easier to detect • Also Radiatively Heated on inside by rest of VV at 150 C • Ignores Conduction from adjacent cells • Representative of Large Un-insulated region • Small Un-insulated regions will be harder to detect

6. ~8” (20cm) ~8” (20cm) Representative Region of VV VV with Bakeout Heating Tubes Courtesy of Mike Cole

7. Portion of Un-insulated VV Exposed to 80K Coil Assumes Only Lower Corner at 150 C dT ~ 34 C